Buckets, especially for bucket dredgers



pt. 25, '1956 F. MACKENZIE 2,763,945

BUCKETS, ESPECIALLY FOR BUCKETDREDGERS Filed July 1, 1952 4 Sheets-Sheet 1 wmw Sept; 25, 1956 F. MACKENZIE BUCKETS', ESPECIALLY FOR BUCKET DREDGERS 4 Sheets-Sheet 2 Filed July 1, 1952 F IG.4

Sept. 25, 1956 F. MACKENZIE BUCKETS, ESPECIALLY FOR BUCKET DREDGERS 4 Sheets-Sheet 3 Filed July 1, 1952 Sept. 25. 1956 F. MACKENZIE BUCKETS, ESPECIALLY FOR BUCKET DREDGERS 4 Sheets-Sheet 4 Filed July 1, 1952 FIGS In 1/6/77 0! Pram/f MQC fM e Unitcd States Patent 2,763,945 BUCKETS, ESPECIALLY FOR BUCKET DREDGERS Application July 1, 1952, Serial No. 296,624 Claims priority, application Netherlands July 4, 1951 8 Claims. (Cl. 37-191) This invention relates to a bucket, especially for bucketdredgers, having a side wall projecting from a bottom with the circumference of the bottom and the free edge of the wall being elliptical.

As the bucket wall is subjected to considerable forces during dredging of the submerged soil, the walls of buckets of the known type are of substantial thickness thereby making the bucket heavy. This results in considerable bucket-weight in comparison with the effective load, so that the proportion between elfective load and dead weight is unfavorable, especially with large buckets.

The main object of the invention is to provide a bucket with a thinner wall and thereby with a lower dead weight, which will however withstand the same substantial forces acting on it during the dredging operation.

Known buckets are provided with a wall, which is fully closed. Therefore, the excess water, contained by the bucket after emerging from the water covering the soil to be dredged, affects the proportion between effective load and dead weight in an unfavorable way.

It is, therefore, another object of the invention to provide a bucket wall through which the excess water may flow off without, however, carrying dredged specie with it.

According to the invention, the bucket is provided with a Wall consisting of two superposed layers of material, each layer comprising a number of narrow strips juxtaposed along their long sides, the strips of one layer crossing the strips of the other layer at an angle.

Other objects and features of the invention will be apparent from the following description in connection with the accompanying drawing. In this drawing two embodiments of the bucket according to the invention are given by way of example.

In the drawing Fig. 1 is a diagrammatic view of the forces acting on the bucket wall.

Fig. 2 is a front elevational view of a first embodiment of a bucket according to the invention.

Fig. 3 is a plan view of this bucket.

Fig. 4 is a side view of this bucket.

Fig. 5 is a development of the bucket wall.

Fig. 6 is a plan view of another embodiment of the bucket.

Fig. 7 is a development of the bucket wall according to the second embodiment.

In Fig. l the direction of the forces in a bucket wall according to the invention consisting of a number of strips with constant width is shown schematically. The wall consists of two contacting layers. Each layer is constructed of a number of strips which are juxtaposed along their long sides, ABCD being a strip of the outer layer and ABFG a strip of the inner layer. The strips of both layers cross at an angle of 60. The strips of both layers are connected or attached to each other at places, determined by the points of intersection of the center lines of gravity. The height of the wall is indicated by H.

P is a force applied to the edge of the wall; it may be, for example the resultant of the forces, working on the edge of the bucket during dredging.

This force divides itself regularly along the line PE in forces P1, applying to the point of intersection of the center lines of gravity. In the drawing there are two forces P1; each force P can only be picked up according to the direction of the center lines Z; the components of P1 being P2 along the center-lines. These components are transferred to the lower edge of the wall via the con nection points of the strips of both layers. There they may be resolved into the components P3 and Pt, of which the forces Pt, act horizontally causing stresses in the wall. The total sum of all forces Pt, as may be seen easily, is zero. Resolution of the forces P3 into P4 and Pa gives a number of horizontal components the sum of which is also zero. It is pointed out, however, that the forces Pt and Pa, although their sum is Zero, do not act in one and the same plane, but in two parallel planes (the inner and outer layer), so that shearing forces appear in the connecting points between the two layers, as well as a bending moment. The required dimensions of the connection means may be derived easily therefrom by simple calculations. The said bending moments, however, do not exceed admissible values.

The sum of the resulting vertical forces P4 is of course equal to P, but this force is spread over the big surface having a length CDEFG so that the resulting compressive stresses are low.

The wall must not only be resistant to compression but also to buckling. However, it has been proved that the collapsing forces are also spread, so that no buckling occurs in practice.

All these circumstances together are much more favorable than with a bucket having a wall which consists of one layer or sheet, the thickness of which is equal to the total thickness of both layers of strips, which form the bucket-Wall according to the invention. It is not possible to determine exactly the running of the internal stresses in a single plate; it is, however, certain that these stresses are spread much less than by the construction according to the invention. Thereby the danger of buckling in a single plate is far greater.

Quite the same line of argument may be applied to a bucket wall, which consists of two layers of strips, the Width of each decreasing in the direction of the bottom of the bucket, the strips being trapezoidal in shape. The angle at which the strips of both layers cross each other has preferably a maximum value of 60 in the middle of the development (Fig. 7) the middle being the point at which the greatest forces act, and decrease to the ends of the development.

Compared with a sufliciently strong bucket wall constructed in accordance with the known art, the bucket wall according to the invention has a thickness which only amounts to 58% of the conventional thickness. The weight of a bucket of known type without mounting with a volume of e. g. 450 liters amounts to 600 kgs.; by application of the construction according to the invention this weight becomes about 350 kgs. The weight of the mounting in both cases may be estimated at kgs. The weight of the bolts and links for each bucket may be estimated at 400 kgs. The weight of the contents with a specific weight of 1.5 amounts to 675 kgs. The known bucket therefore weighs 600+l00 +675+400= 1775 kgs. The bucket according to the invention weighs 250 kgs. less, thus 1525 kgs.

A saving of power to be delivered is also obtained, as an important smaller weight is to be lifted along the ladder. The saving of weight amounts to 250 kgs. or about 14%. This means a saving of power of the same amount to a bucket-dredger, fitted with buckets according to the invention, because the buckets are to be lifted along the ladder, the bucket being filled during this liftlng.

Finally less wear of all rolling parts is obtained by reason of the smaller weight.

In the Figs. 2-5 a first embodiment of the bucket according to the invention is shown. In Fig. 2 the bucket is seen according to arrow II in Fig. 4 and in Fig. 5 according to arrow III in Fig. 4. The numeral 1. denotes the bucket as a unit, 2 is the bottom, pressed from a steel plate and 3 is the wall of the bucket. The mounting consists of two attached pieces 4, each having two holes 5 for the bolts with which the chain links 6 are attached pivotally. These links connect the buckets to an endless row, which runs along the ladder and is carried by turning polygons, attached to the ends of the ladder.

The wall, of which a development is shown in Fig. 5, consists of two layers of strips. The full-lined strips are denoted by 7, the dot-lined strips are denoted by 8. Each strip consists of two strip-shaped parts of equal width and of half the strip width, which are connected to each other along their longitudinal edges 9, preferably by Welding. The welds are made in such a way, that they also adhere to the strips of the other layer. Each strip is thus constructed of two strips. Between these doublestrips slots 10 are left free. Apart from being assured that the forces are spread according to the scheme in Fig. 1, the apertures 11 at the crossing of the slots of both layers are advantageous for clean-spouting of the bucket, as the water may flow off through the apertures. The dredged specie, however, is too viscous for flowing through these apertures, so that the output is not decreased.

Apart from this, the strips of both layers are connected to each other at the gravity-centers 12 of the rhombic parts. This connection is preferably made by drilling holes at these gravity-centers, superimposing the corresponding strips and filling these holes by welding. Also sunk rivets could be applied, being, however, a more costly attaching method. Ordinary rivets should be rejected, since for good emptying the inner side of the bucket is to be smooth. The diameter of the holes to be drilled may be calculated in a simple way from the forces to be met.

The bottom of the bucket is preferably attached to the wall by welding.

A remarkable advantage of the embodiment of the bucket, of which Fig. 6 is a side view and Fig. 7 is a development, is the fact that a separate welding joint becomes superfiuous. In the first embodiment this welding joint is denoted by 13 (see Figs. 3 and 5). The taper of the strips is determined by the difference of the circumferential length between mouth and bottom.

An advantage of the first embodiment compared with the second one is greater ease of manufacture of the strips. Shearing of strips with a constant width is easier than shearing tapered strips.

It will be clear that the inventive idea is not limited to the shown embodiments. A great number of variations may be possible within the scope of the invention.

We claim:

1. A'dredging bucket for use in a dredge comprising a metallic bucket body and means for mountingsaid body on the dredge chain, said body comprising an elliptical bottom and a frusto-conical wall connected to the periphery of the bottom, said wall having anelliptical free edge and being formed from two superposed plies, each ply comprising a plurality of individual flat strips of uniform thickness juxtaposed along their longitudinal edges, each strip of one ply crossing a plurality of strips of the other ply at an oblique angle and each strip being secured directly to each strip which it crosses.

2. A dredging bucket for use in a dredge comprising a metallic bucket body and means for mounting said body on the dredge chain, said body comprising an elliptical bottom and a frusto-conical wall connected to the periphery of the bottom, said wall having an elliptical free edge and being formed from two superposed plies, each ply comprising a plurality of individual flat strips of uniform thickness and uniform length juxtaposed along their longitudinal edges, each strip of one ply crossing a plurality of strips of the other ply at an oblique angle and each strip being secured directly to each strip which it crosses.

3. A dredging bucket for use in a dredge comprising a metallic bucket body and means for mounting said body on the dredge chain, said body comprising an elliptical bottom and a frusto-conical wall connected to the periphery of the bottom, said wall having an elliptical free edge and being formed from two superposed plies. each ply comprising a plurality of individual flat strips of uniform thickness and uniform length juxtaposed along their longitudinal edges, each strip of one ply crossing a plurality of strips of the other ply at an angle of about 60 and each strip being secured directly to each strip which is crosses.

4. A dredging bucket for use in a dredge comprising a metallic bucket body and means for mounting said body on the dredge chain, said body comprising an elliptical bottom and a frusto-conical wall connected to the periphery of the bottom, said wall having an elliptical free edge and being formed from two superposed plies, each ply comprising a plurality of individual fiat strips of uniform thickness juxtaposed along their longitudinal edges, each strip of one ply crossing a plurality of strips of the other ply at an oblique angle and each strip being secured directly to each strip which it crosses, said strips tapering in extending from said free edge toward said bottom.

5. A dredging bucket for use in a dredge comprising a metallic bucket body and means for mounting said body on the dredge chain, said body comprising an elliptical bottom and a frusto-conical wall connected to the periphery of the bottom, said wall having an elliptical free edge and being formed from two superposed plies, each ply comprising a plurality of individual flat strips of uniform thickness juxtaposed along their longitudinal edges, each strip of one ply crossing a plurality of strips of the other ply at an angle of 60 and each strip being secured directly to each strip which it crosses, said strips tapering in extending from said free edge toward said bottom.

6. A dredging bucket for use in a dredge comprising a metallic bucket body and means for mounting said body on the dredge chain, said body comprising an elliptical bottom and a frusto-conical wall connected to the periphery of the bottom, said wall having an elliptical free edge and being formed from two superposed plies, each ply comprising a plurality of individual flat strips of uniform thickness juxtaposed along their longitudinal edges, each of said strips consisting of two equal parts welded together along their longitudinal meeting edges, each strip of one ply crossing a plurality of strips of the other ply at an oblique angle and each strip being secured directly to each strip which it crosses.

7. A dredging bucket for use in a dredge comprising a metallic bucket body and means for mounting said body on the dredge chain, said body comprising an elliptical bottom and a frusto-conical wall connected to the periphery of the bottom, said wall having an elliptical free edge and being formed from two superposed plies, each ply comprising a plurality of individual flat strips of uniform thickness juxtaposed along their longitudinal edges and spaced from one another to define a slot between adjacent strips, each strip of one ply crossing a of the other ply at an oblique angle and secured directly to each strip which it plurality of strips each strip being crosses.

8. A dredging bucket for use in a dredge comprising a metallic bucket body and means for mounting said body on the dredge chain, said body comprising an elliptical bottom and a frusto-conical wall connected to the periphery of the bottom, said wall having an elliptical free edge and being formed from two superposed plies, each ply comprising a plurality of individual flat strips of uniform thickness juxtaposed along their longitudinal edges, each strip of one ply crossing a plurality of strips of the other ply at an oblique angle, said strips being formed With registering apertures and each strip being secured directly to each strip which it crosses by means of a weld deposit in lapping strips.

the registering apertures in the over- 10 References Cited in the file of this patent UNITED STATES PATENTS Srnyth et a1. Jan. 5, 1904 Sedlacek Nov. 28, 1905 Young Aug. 23, 1932 FOREIGN PATENTS Great Britain of 1890 Great Britain of 1909 OTHER REFERENCES The Welding E ngineer Pub. Co., New York, 1947, p. 504. 

